title: Stability of oxyhemoglobin affinity in patients with obstructive sleep apnea-hypopnea syndrome without daytime hypoxemia.
abstract: A decrease in hemoglobin affinity for oxygen is considered an adaptive mechanism against tissue hypoxia. Obstructive sleep apnea-hypopnea syndrome (OSAHS) is characterized by recurrent episodes of apnea and hypopnea resulting in arterial oxygen desaturations during sleep. Maillard et al. (10) observed a right shift of the oxyhemoglobin dissociation curve (ODC) and an increase in 2,3-diphosphoglycerate (2,3-DPG) concentration ([2,3-DPG]) in 15 patients with severe OSAHS, but some had slight daytime arterial hypoxemia while breathing room air. The aim of our study was to measure the ODC and 2,3-DPG concentrations in a group of subjects normoxemic during daytime referred to our sleep laboratory for suspicion of snoring or OSAHS. The patients were recruited during a period of 6 mo. All arterial and venous blood samples were taken early in the morning within 1 h of awakening following a full-night polysomnography. ODC and 2,3-DPG were analyzed in 88 patients: 56 OSAHS (oxygen desaturation index: 27.5 +/- 24.5) and 32 non-OSAHS. We found a significant correlation between the P50 and 2,3-DPG levels in the 88 patients: r = 0.502, P < 0.001. We observed no difference between OSAHS and non-OSAHS for the P50 and for [2,3-DPG]. There was no correlation between the severity of OSAHS and either P50 or [2,3-DPG]. Finally, there was no change in these parameters measured at baseline, after 3 days and after 1 mo of treatment by nasal continuous positive airway pressure in 7 patients with OSAHS. We conclude that patients with OSAHS who are normoxemic during daytime have comparable oxyhemoglobin affinity than nonapneic subjects.
authors.affiliation: Pneumology Unit, Cliniques Universitaires Saint-Luc (UCL Ave. Hippocrate 10, 1200 Brussels, Belgium.
authors.forename: Didier
authors.initials: D
authors.lastname: Clause
authors.forename: Bruno
authors.initials: B
authors.lastname: Detry
authors.forename: Daniel
authors.initials: D
authors.lastname: Rodenstein
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Liistro
mesh_terms: D019794:2,3-Diphosphoglycerate / Q000097:blood; D000328:Adult; D001784:Blood Gas Analysis; D015992:Body Mass Index; D045422:Continuous Positive Airway Pressure; D005260:Female; D006801:Humans; D000860:Hypoxia / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D010755:Organophosphates / Q000097:blood; D010100:Oxygen / Q000097:blood; D010108:Oxyhemoglobins / Q000378:metabolism*; D017286:Polysomnography; D020181:Sleep Apnea, Obstructive / Q000378:metabolism* / Q000628:therapy
chemical_list: D010755:Organophosphates; D010108:Oxyhemoglobins; D019794:2,3-Diphosphoglycerate; D010100:Oxygen